Going crazy, AF late

Courtney
Ok, so AF was due yesterday and nothing. It doesn't even feel like I'm going to start. I have lower back pain, but no cramps. I have bloating and gas though. I spotted once when I wiped on Saturday night. So it's been 6 days. But every test I take is negstive. Oh, I'm never late by the way. I'm usually right on time, or rarely early. I did get a BFP in January, but I miscarried. I got it when I was one day late. I guess I want to know if I could be pregnant? If each pregnancy is different with respect to when you test positive? Any help would be appreciated!!